[Gutter][View Registry] Add Gutter view providers to the ViewRegistry

src/gutter-component-helpers.coffee

@@ -1,6 +1,18 @@
 # Helper methods shared among GutterComponent classes.
 
 module.exports =
+  createGutterView: (gutterModel) ->
+    domNode = document.createElement('div')
+    domNode.classList.add('gutter')
+    domNode.setAttribute('gutter-name', gutterModel.name)
+    childNode = document.createElement('div')
+    if gutterModel.name is 'line-number'
+      childNode.classList.add('line-numbers')
+    else
+      childNode.classList.add('custom-decorations')
+    domNode.appendChild(childNode)
+    domNode
+
   # Sets scrollHeight, scrollTop, and backgroundColor on the given domNode.
   setDimensionsAndBackground: (oldState, newState, domNode) ->
     if newState.scrollHeight isnt oldState.scrollHeight